<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Deml</title>
    <style type="text/css">
        * {
            margin: 0;
            padding: 0;
            text-decoration: none;
        }

        body {
            padding: 20px;
        }

        #container {
            width: 600px;
            height: 400px;
            overflow: hidden;
            position: relative;
            border: 1px solid #ccc;
        }

        #list {
            width: 4200px;
            position: absolute;
            z-index: 1;
        }

        img {
            width: 600px;
            height: 400px;
            float: left;
        }

        #buttons {
            position: absolute;
            height: 10px;
            width: 100px;
            z-index: 2;
            bottom: 10px;
            left: 250px;
        }

        #buttons span {
            cursor: pointer;
            width: 10px;
            height: 10px;
            border-radius: 50%;
            float: left;
            border: 1px solid #fff;
            margin: 0 4px;
        }

        #buttons .on {
            background: orangered;
        }

        .arrow {
            display: none;
            cursor: pointer;
            line-height: 36px;
            font-size: 36px;
            font-weight: bold;
            text-align: center;
            width: 40px;
            height: 40px;
            position: absolute;
            z-index: 2;
            top: 180px;
            color: #ffffff;
            background: rgba(0, 0, 0, .3);
        }

        .arrow:hover {
            background: rgba(0, 0, 0, .7);
        }

        #container:hover .arrow {
            display: block;
        }

        #prev {
            left: 20px;
        }

        #next {
            right: 20px;
        }
    </style>
    <script type="text/javascript">
        window.onload = function () {
            var container = document.getElementById("container");
            var list = document.getElementById("list");
            var buttons = document.getElementById("buttons").getElementsByTagName('span');
            var prev = document.getElementById('prev');
            var next = document.getElementById('next');
            var index = 1;
            var animated = false;
            var timer;

            function showButton() {
                for (var i = 0; i < buttons.length; i++) {
                    if (buttons[i].className == 'on') {
                        buttons[i].className = '';
                        break;
                    }
                }
                buttons[index - 1].className = 'on';
            }

            function animate(offset) {
                animated = true;
                var newLeft = parseInt(list.style.left) + offset;

                var time = 300;// 位移总时间
                var interval = 5;// 时间间隔
                var speed = offset / (time / interval);// 每次位移量
                go();

                function go() {
                    if ((speed > 0 && parseInt(list.style.left) < newLeft) ||
                        speed < 0 && parseInt(list.style.left) > newLeft) {
                        list.style.left = parseInt(list.style.left) + speed + 'px';
                        setTimeout(go, interval);
                    } else {
                        animated = false;
                        list.style.left = newLeft + 'px'
                        if (newLeft > -600) {
                            list.style.left = -3000 + 'px'
                        }
                        if (newLeft < -3000) {
                            list.style.left = -600 + 'px'
                        }
                    }
                }

                // list.style.left = parseInt(list.style.left) + offset + 'px';
                // if(newLeft > -600 ){
                //     list.style.left = -3000 + 'px'
                // }
                // if(newLeft < -3000){
                //     list.style.left = -600 + 'px'
                // }
            }

            function play(){
                timer = setInterval(function () {
                    next.onclick();
                },3000)
            }

            function stop(){
                clearInterval(timer);
            }

            container.onmouseover = stop;
            container.onmouseout = play;

            play();


            next.onclick = function () {
                if (!animated) {
                    if (index == 5) {
                        index = 1;
                    } else {
                        index += 1;
                    }
                    showButton();
                    animate(-600);
                }
            }

            prev.onclick = function () {
                if (!animated) {
                    if (index == 1) {
                        index = 5;
                    } else {
                        index -= 1;
                    }
                    showButton();

                    animate(600);
                }
            }

            for (var i = 0; i < buttons.length; i++) {
                buttons[i].onclick = function () {
                    if (!animated) {
                        if (this.className == 'on') {
                            return;
                        }
                        var myIndex = parseInt(this.getAttribute("index"));
                        var offset = (myIndex - index) * -600
                        animate(offset);
                        index = myIndex;
                        showButton();
                    }
                }
            }

        }
    </script>
</head>
<body>
<div id="container">
    <div id="list" style="left:-600px;">
        <img src="images/5.jpg">
        <img src="images/1.jpg">
        <img src="images/2.jpg">
        <img src="images/3.jpg">
        <img src="images/4.jpg">
        <img src="images/5.jpg">
        <img src="images/1.jpg">
    </div>
    <div id="buttons">
        <span index="1" class="on"></span>
        <span index="2"></span>
        <span index="3"></span>
        <span index="4"></span>
        <span index="5"></span>
    </div>
    <a href="javascript:;" class="arrow" id="prev">&lt;</a>
    <a href="javascript:;" class="arrow" id="next">&gt;</a>
</div>
</body>
</html>